Apparatus for mixing slurry.



A. SCHRUDER.

APPARATUS FOR MIXING SLURRY.

APPLICATION FILED FEB. 24, 1914.

1,137,294, Patented Apr. 27, 1915.

WITNESSES l/Vl/E/VTOR Q 0 1.3;- 5 M M w M W Geodn A T ORIVEYS UNITED STATES PATENT OFFICE.

AAGE SCHRODEB, OF CHARLOTTENLUND, DENMARK, A SSIGNOR TO F. L. SMIDTH & CO., OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

APPARATUS FOR MIXING SLURRY.

Specification of Letters Patent.

Patented Apr. 2'7, 1915.

Application filed February 24, 1914. Serial No. 820,789.

To all whom it may concern:

Be it known that I, AAGE Sormfinnn, a subject of the King of Denmark, and residing in Hovmarksvej 6, Charlottenlund, Denmark, have invented certain new and useful Improvements in Apparatus for Mixing Slurry, of which the following is a specification, reference being had to the accompanying drawings, forming a part hereof.

This invention relates to apparatus for mixing slurry or other material presenting the difficulties of mixing hereinafter men- 7 tioned.

It is generally recognized that the mixing of comparatively thin slurry, that is, slurry containing a relatively large proportion of water, may be accomplished satisfactorily by the use of a mechanical agitator, while the mixing of thick slurry, that is, slurry containing a relatively small proportion of water, presents serious difliculties owing to the cohesion of the particles in the mass and the consequent formation of channels more or less well defined through which the means for accomplishing the mixing, whether a current of air or other means may continue to pass without agitating or mixing the slurry.

It is the principal object of this invention to provide an apparatus for mixing thick slurry which shall overcome the difficulty referred to and which shall insure a complete agitation and intermixture of all of the constituent parts of the composition which is to be mixed.

It has been proposed to mix slurry by means of mechanical agitators comprising generally moving arms disposed within the mass of slurry and by the provision directly in the mechanical agitator of jets of air. mechanical agitator alone is inadequate because the moving arms quickly formregular channels through which they may pass with little resistance and without stirring or mixing of the mass, and the use of air discharged directly from the mechanical agitator is open to the same objection inasmuch as the moving arms follow their respective paths without difiiculty and the air, seeking the path of least resistance, passes through the interstices of the mass and also establishes channels between the points of discharge and the surface of the slurry through which it may continue to pass, the movement of the arms of the agitator having little effect on such air channels.

In accordance with the present invention it is proposed to provide preferably both in the side wall and the bottom of the container, a series of fixed nozzles through which may be discharged into the slurry a like number of air jets, in combination with a mechanical agitator constructed and mounted within the container in such manner as to destroy continually the channels which the air jets tend to form between their respective points of'discharge and the surface of the slurry. In the preferred embodiment, the mechanical agitator comprises a vertical, rotatable shaft carrying a series of arms horizontally disposed at different heights in the slurry, whereby the aforesaid air channels will be continually interrupted at several points along their length and the mixing of the material more efliciently and effectively accomplished. If desired, the mechanical agitator itself may be provided with air jets discharging therefrom in such manner as to assist in the agitation of the material and the propulsion of the agitator in a manner well known in the art of reaction motors.

The invention will be described more particularly with reference to the accompanying drawings, in which Figure 1 is a fragmentary view partly in section of an apparatus embodying the present invention and showing the stationary nozzles disposed in the walls of the container and the relatively movable nozzles mounted on the mechanical agitator. Fig. 2 is a view in plan of so much of the apparatus as is illustrated in Fig. 1.

This invention is not concerned with the character of the container a, although in practice it will be found convenient to employ concrete therefor, thus permitting the openings for the nozzles of the air jets to be readily cast in situ. Within the'container a are mounted in a substantially vertical position a series of rotatable shafts b which may be propelled through the reaction of the air upon the mass of the slurry as the air is discharged from the arms of the mechani- ;cal agitator, or by means of any available external sourc of power,indicated generally herein as a driving gear I). All of the shafts b and their associated parts are similar, so

that a description of one will sufiice for all. On the shaft 6 are fixed at suitable intervals a series of arms I; disposed substantially in a horizontal position within the container aand movable through the mass of the slurry to agitate the same when the shaft is rotated. In the illustrated form, the arms I) and shaft 5 are hollow, to permit the passage therethrough of compressed air which is discharged at points along the arms I). through suitable nozzles b for the purpose of assisting further in the agitation and mixing of the constituents of the slurry. It will be evident that as the air is discharged through the nozzles I) under relatively high pres sure, it will react on the mass of the slurry and tend to impel the entire agitator. Whether or not this force of reaction is sufficient for the purpose of rotating the shaft ,6 with the arms 6 will depend on conditions not connected with the subject matter of this invention, but it is to be noted that the construction is especially desirable inasmuch as the force of reaction will, at least,. always assist in the movement of said arms.

The compressed air may be derived from any available source and is indicated herein as being led to the container a and shaft 6 through'a feed pipe 0. This feed pipe 0 will, of course, be of such form as to supply air to the stationary nozzles (Z, wherever the latter may be located, the successful practice of the invention demanding that such nozzles should be disposed throughout the bottom of the container and also along the side walls thereof at varying elevations. It will be appreciated that conditions surrounding the use of the improved apparatus may differ and such differences will determine the number of stationary air jets to be employed and their preferred location, the provision of a manually operable valve d for ployed Iosed substantially horizontally at difiereiiflbvels each nozzle (1 permitting the operator to meet all such changing conditions as experience may dictate. For the sake of convenience, one of the nozzles e extends directly into the vertical'shaft b and discharges its jets thereinto, to feed the several nozzles 15 mounted on the moving arms-b This nozzle e may be substantially similar to the other nozzles d, although it appears that it has the additional function of constituting a glulide for the lower end of the shaft 6.-

operation, the several jets of air discharged through the nozzles d seek to find ready paths through the interstices of the,

mass'of slurry and form channels between the several points of discharge and the surface of the slurry. Such channels cannot remain when the present apparatus is emsince the rotating arms '6,

m ths mass of the slurry, sweep across such air channels and destroy them continually, not only agitat ng the material meanwhile the. surface of the slurry.

mg the air suddenly to seek other passages.

Such agitating action of the air jets of the stationary nozzles and the mechanical agitator is furthered by the several blasts of air constantly discharged through the nozzles b which are constantly carried from one portion of the material to another and which not only in themselves agitate the material but assist further in tearing down the channels which tend to form under the action of the air jets of the stationary nozzles and the movement of the arms I).

The improved apparatus, for the reasons pointed out, not only assures the eifective mixing of the constituents of the slurry but is highly eflicientin its operation since the full effects of the several air jets are utilized atall times and the mechanical agitator is constantly engaged in its work of assisting the air jets in their action and in agitating the mass in which it is moved.

Modifications in the details of the structur may be made as well as rearrangements into the slurry below its surface, and memeans arranged to operchanical agitatin ate in the slurry in planes between the nozzles and the surface of the slurry.

2. An apparatus for agitating thick slurry or the like comprising a container for the slurry, nozzles arranged in the bottom of the container and adapted to discharge air into of the nozzles and moving portions of the v a container for the Y the slurry, and mechanical agitators arranged to operate between the nozzles, and

the surface of the slurry'.

3. An apparatus for agitating thick slurry or the like comprising a container for the slurry, nozzles arranged in the bottom and sides of the container and-adapted to discharge air into the slurry, and a mechanical agitator between the nozzles in the bottom and the surface of the slurry.

4. An apparatus for agitating thick slurry or the like comprising a container for the slurry, nozzles arranged in the bottom of the container and arran d to discharge ammto the slurry, a mcchamcal a 'tator comprising a series of arms provide with nozzles ar ranged to discharge air into the slurry and adapted to operate between the nozzles arrangedin the bottom of the container and 5. An apparatus for agitating thick slurry or the like to prevent the precipitation of the solid particles to the bottom including a container for the slurry, fixed nozzles to permit the discharge of air jets into the slurry to agitate it and mechanical agitating means disposed operatively within the container between the nozzles and the surface of the slurry to agitate the slurry, said means including moving arms disposed at different levels Within the slurry.

6. An apparatus for agitating thick slurry or the like to prevent the precipitation of the solid particles to the bottom including a container for the slurry, fixed nozzles to permit the discharge of air jets into the slurry to agitate it and mechanical agitating means disposed operatively within the container between the nozzles and the surface of the slurry to agitate the slurry, said means including horizontal, moving arms disposed at different levels within the slurry.

7. An apparatus for agitating thick slurry or the like to prevent the precipitation of the solid particles to the bottom including a container for the slurry, valve controlled nozzles at different levels to permit the discharge of air jets into the slurry to agitate it and a mechanical agitator disposed operatively within the container between the nozzles and the surface of the slurry to agitate the slurry, said agitator comprising a vertical, rotating shaft and a series of arms mounted radially thereon at different levels.

8. An apparatus for agitating thick slurry or the like to prevent the precipitation of the solid particles to the bottom comprising 9. An apparatus for agitating thick slurry or the like to prevent the precipitation of the solid particles to the bottom comprising a container for the slurry, valve controlled nozzles passing through the bottom of the container and through the side walls thereof at different levels to permit the discharge of air jets into the slurry to agitate it, a mechanical agitator disposed operatively within the container between the nozzles and the surface of the slurry to agitate the slurry, said agitator comprising a vertical, rotating shaft and a series of arms mounted radially thereon at different levels and Iiozzles carried on said arms through which is discharged air received through the shaft and the arms, the air jets from the last named nozzles reacting with the slurry in a manner to tend to move said arms and rotate the shaft.

This specification signed and witnessed this 4th day of February A. D. 191;}

AAGE SCHRODER. Signed in the presence of-- CHR. ENGELHART, F. S. THIELEE. 

